A study of symmetry breaking in a relativistic Bose gas using the contraction algorithm

Understand

A relativistic Bose gas at finite density suffers from a sign problem that makes direct numerical simulations not feasible.

• One possible solution to the sign problem is to re-express the path integral in terms of Lefschetz thimbles.
• Using this approach we study the relativistic Bose gas both in the symmetric phase (low-density) and the spontaneously broken phase (high-density).
• In the high-density phase we break explicitly the symmetry and determine the dependence of the order parameter on the breaking.